coming in but as of now there is no certain match and they are, again, using all their computers and technology to try to, as the names come in, to try to find them and find out which tips are more credible than the others. >> i'm wondering, jonathan, if you were in that crowd and survived and you're watching right now, does the human memory work that way that you would recognize these two guys walking along dressed as they were? >> i don't know. looking over the videotapes of that crowd, people were coming, going, celebratory, people watching the race, looking out on to the marathoners finishing up looking for their friends, loved ones, and probably not paying attention as closely to people around them. so i'm not exactly sure unless something stood out and my speculation is that someone noticed this guy in the white hat and setting something down, perhaps somebody remembers that and thought that's strange. but looking at this videotape, it just looks like ordinary guys in their 20s walking along this marathon route near the end of the race. >> or, to be honest about it and complete, guys dres